B 12r and B 12s can be prepared from cyanocobalamin by controlled potential reduction, or chemical reduction using sodium borohydride in alkaline solution, zinc in acetic acid, or by the action of thiols
PMC 4558874
Here, the glutathione is contained within a casing made from phospholipids, liposomes, which protect it from digestive secretions and ensure it completes its journey to the intestinal barrier in its reduced form (9)
Suzuki, H., Yamashiro, D., Ogawa, S., Kobayashi, M., Cho, D., Iizuka, A., Takada, M., Isokawa, M., Nagao, K., & Fujiwara, Y
The second way of course is reducing exposure